Research and Development on the First-loading Coated Fuel Particles for the 10 MW High Temperature Gas-cooled Reactor

The 10 MW high temperature gas-cooled reactor (HTR-10) project uses spherical fuel elements with all ceramic TRISO type coated particles. The TRSIO type coated fuel particle consists of a microspherical fuel kernel and coating layers of porous pyrolytic carbon, inner dense pyrolytic carbon, pyrolytic silicon carbide and outer dense pyrolytic carbon. A new type of spouted bed with multiple gas inlets and the successive four-layer coating processes were investigated for fabricationg coated fuel particles. The first-loading coated fuel particles for HTR-10 project were fabricated in a 150 mm diameter fluidized bed coater by chemical vapor deposition. The microstructure of coated fuel particles was observed using scanning electron microscope. The failure rate of as-fabricated coated fuel particles is 3. 4 × 10 -6. The result of irradiated experiments for coated fuel particles, the R/B ratio of the fission product 85Krm is in the range of 10-6, shows that the properties of coated fuel particles can meet the design specification of THR-10.